Punch.



Fatented July 14, 1903.

PATENT OFFICE.

CHARLES S. DUNDORE, OF READING, PENNSYLVANIA.

PUNCH.

SPECIFICATION forming part of Letters Patent No. 733,544, dated July 14, 1903.

Application filed December 26,1902. Serial No. 136.628. (No model.)

To [tZZ whom it may concern;

Be it known that 1, CHARLES S. DUNDORE, a citizen of the United States of America, and a resident of Reading, in the county of Berks and State of Pennsylvania, have invented certain new and useful Improvements in Punches, of which the following is a specification.

My invention relates to certain improvements in punches and the manner of securing the same to the stock, the main object of which is to provide a punch of economical construction which may be secured or removed with the greatest facility and which will be positively retained with the stock in the withdrawing movement of the latter.

The invent-ion is fully described in connection with the accompanying drawings, and the novel features are particularly pointed out in the claims.

Figure 1 shows my improved punch and coupling means therefor in operative position. Fig. 2 is a similar view showing the parted cone-head loosened by a partial withdrawal of the coupling-nut sufficient to permit of the insertion or removal of the punch. Fig. 3 is a plan view of the parted cone-head for the punch.

A represents the stock or ram, to which the punch is secured by means of a coupling-nut B of well-known form and a parted cone-head G, fitted to the tapered aperture in the depending portion of said nut, the latter being screwed upon the stock A, as usual, to firmly press the cone-head segments against the shank of the punch, and thereby center and secure the latter.

Owing to the great strain to which the punch is frequently subjected in Withdrawing it from the punched sheet it is practically important that a positive engagement should be provided between the punch and the chucking means therefor, and the purpose of my invention is to provide for such a positive engagement while at the same time making the punch itself of simple and economical construction and enabling it to be inserted or removed by merely loosening the coupling. To this end I preferably form the punch from a rolled bar of steel of the size desired for the cylindrical shank portion 1 thereof, cut one or more cross-grooves 2 in the periphery of said shank portion, and reduce the projecting punching portion 3 thereof to the desired size with a centering-teat 4, as usual. I thus avoid any unnecessary cutting away of metal andproduce the punch with a minimum amount of material and labor, while at the same time providingfor a positive engagement of the punch by means of said groove 2 with the cone-head segments, which, as shown, are formed with corresponding 0&- sets or ribs 5, adapted to enter said groove when the coupling-nut is drawnup to clamp the punch, thereby positively preventing the pulling out of the punch from the chucking mechanism in withdrawing it from the punched metal. 'Moreover, the strain thus put upon the punch is mainly at the upper portion thereof, where the groove 2 is preferably located and adjacent to which the inclosing coupling-nut is of greatest diameter and strength.

To facilitate the insertion and removal of the punch, I preferably bevel the edges 6 and 7 of the latter which come in contact with the ofisets or shoulders on the cone-head segments, so as to adapt the punch to push aside said segments out of its path when they have been loosened by the partial withdrawal of the coupling-nut, as indicated in Fig. 2, either for the purpose of inserting or removing the punch.

In order to leave the cone-head segments free to adjust themselves within the tapered aperture of thecoupling nut, so as to perfectly engage the incut or shouldered punch shank, I provide that the end of the latter shall extend slightly beyond the cone-head, thus having the latter free from contact with the stock or ram, against which the punch itself abuts.

The construction shown may evidently be modified without departing from my invention*as, for instance, by reversing the location of the engaging offset andgroove or shoulder, respectively, or in other obvious ways.

1. The combination with a punch couplingnut having a tapered aperture, of a punch having a cylindrical shank with incut peripheral surface, and a parted hollow cone-head adapted to be pressed into positive engage Ice ment with said incut shank of the punch, said punch being beveled so as to Wedge apart the loosened cone-head segments and permit the passage of the punch substantially as set forth.

2. The combination with a punch couplingnut having a tapered aperture, of a parted cone-head for a punch, fitted to said aperture and formed with a cylindrical bore having a circular offset therein, and a punch having a cylindrical shank formed with a circular groove to receive said offset substantially a set forth.

3. The combination with a punch couplingnut having a tapered aperture, of a parted cone-head for a punch, fitted to said aperture and formed with a cylindrical bore having a circular ofiset therein, and a punch having a cylindrical shank formed with a circular groove to receive said offset, the edges on the punch being beveled to adapt the same to wedge apart the loosened cone-head segments and permit the passage of the punch substantially as set forth,

4. The combination with a punch couplingnut having a tapered aperture, of a parted cone-head fora punch, fitted to said aperture and formed with a cylindrical bore having a circular offset therein, and a punch having a cylindrical shank formed with a circular groove to receive said ofiset, said shoulder being so located relative to the engaging ofiset in the cone-nut as to cause the end of the engaged punch-shank to project beyond the cone-nut substantially as set forth.

Signed at Reading, Pennsylvania, this 15th day of December, 1902.

CHARLES S. DUNDORE.

\Vitnesses:

D. M. STEWART, W. G. STEWART. 

